How to drill, cut, and engrave traceable QR codes on PCB? This requires understanding of RFH UV laser technology.   Ultraviolet laser has a wavelength of 355nm, which is a cold light source. The heat affected zone of laser cutting is particularly small as 10μm and will not produce thermal effects. Therefore, when drilling, cutting and engraving high-precision and high-level PCB circuit boards, no burrs will be produced , and it will also not causes deformation or scorching problems. UV laser are better than CO2 and fiber lasers.